This invention relates to an integrated vehicle control system which allows each electronic control apparatus to transmit and receive various data to and from other electronic control apparatuses for controlling various functions of a vehicle.
In vehicles, especially in automotive vehicles, to satisfy recent market requirements including saving of fuel, improvement of safety, and improvement of convenience, many of the devices installed in an automotive vehicle are electronically controlled. To realize correlated operations and share mutual control information among electronic control apparatuses (hereinafter, referred to as ECU), respective ECUs are connected with each other via a common communication line so as to constitute a network (so-called LAN) to execute data communication.
For example, FIG. 7 shows an example of this kind of conventional network including a control device network 100, an information device (AVC device) network 110, and a body device network 120 which are distinctive network groups separated according to the classification of their fields.
The control device network 100, for various control devices installed in a vehicle, includes an engine ECU 101 controlling an engine, an ACC/ECU 102 executing a cruise control for adjusting a distance to a preceding vehicle traveling ahead of this vehicle or fixing a traveling speed of this vehicle to a constant value according to user's preference, an ECT(i.e., Electrically Controlled Transmission)/ECU 103 executing a gear shift control for an automatic transmission installed in the vehicle, and a brake ECU 104 controlling the braking device, which are connected to each other via a communication line La.
The AVC (i.e., Audio Video Control) device network 110, for various information devices installed in the vehicle, includes a navigation ECU 111 controlling a navigation device, an audio ECU 112 controlling an audio device, and a TEL/ECU 113 controlling a telephone device, which are connected to each other via a communication line Lb.
The body device network 120, for various body accessories installed in the vehicle, includes a power source ECU 121 administratively controlling the electric power of a vehicle battery, a body ECU 122 controlling lock/unlock of doors, and a smart key ECU 123 instructing lock/unlock of doors to the body ECU122 based on a transmitted waveform from an electronic key of a user and also permitting startup of the engine according to user's operation, which are connected to each other via a communication line Lc.
Furthermore, a gateway ECU 130 is provided for relay of data among respective networks (i.e., among the communication lines La, Lb, and Lc). The gateway ECU 130 allows individual ECUs belonging to mutually different networks to exchange their data (for example, refer to FIG. 2 of the Japanese Patent Application Laid-open No. 5-85228 (1993) corresponding to the U.S. Pat. No. 5,351,776; FIG. 1 of the Japanese Patent Application Laid-open No. 10-250417 (1998) corresponding to the U.S. Pat. No. 6,154,688, and FIG. 2 of the Japanese Patent Application Laid-open No. 2000-71819 corresponding to the U.S. Pat. No. 6,292,741.
However, according to the integrated vehicle control system using the above-described conventional network, it was difficult to efficiently execute abnormality detection ranging widely and covering the entire apparatuses of this control system.
More specifically, according to the conventional integrated vehicle control system, each ECU connected to the communication line obtains various data (i.e., control information and requests) from other ECUs, and determines control amounts to be supplied to its managing devices and controls the devices based on the determined control amounts for realizing intended controls. In this respect, each ECU operates independently or selfishly and determines the behavior based on its own intent or judgment. Accordingly, it was inevitably necessary to give the abnormality detecting function to each ECU, so that each ECU can detect any abnormality occurring in the inside of each ECU or in its managing control objective devices. In other words, it was impossible to execute detailed abnormality detection capable of ranging widely and covering the entire apparatuses of the control system and accurately identifying the root of each abnormality.
For example, the automatic transmission may fail to smoothly execute the gear shift operation. The cause of this failure may reside in the automatic transmission itself, or may be originated from an engine when the engine has abnormality in its output torque. According to the conventional system shown in FIG. 7, even if the failure of the gear shift operation is originated from the engine having abnormality in its output torque, the ECT/ECU 103 will judge it as the failure caused in the automatic transmission itself. Then, to eliminate, correct, or avoid the detected abnormality, the ECT/ECU 103 executes fail-safe processing applied to the automatic transmission.
Furthermore, due to abnormality of engine output, the cruise control or the traction control may not be performed appropriately. In such a case, instead of the engine ECU 101, the ACC/ECU 102 or the brake ECU 104 is forced to detect the abnormality and execute any fail-safe processing. In this manner, according to the conventional control system, it was usual that the ECU in charge of a post-processing device (such as the automatic transmission, the brake system, or the like) has the responsibility against the abnormality occurring in a preprocessing device (such as the engine) managed by other ECU.
Furthermore, according to the above-described conventional integrated vehicle control system, the data amount (i.e., communication data volume) transmitted or received via the communication line is so large that the recent requirements for multi-functions and high performance cannot be realized.
Namely, according to the conventional integrated vehicle control system, as described previously, each ECU operates independently or selfishly and determines the behavior based on its own intent or judgment. If required to smoothly control various devices installed in a vehicle based on mutual cooperation, respective ECUs are required to speedily exchange many and various kinds of required data. For example, according to the conventional example shown in FIG. 7, to smoothly control the engine and the automatic transmission, the engine ECU 101 must supply various control data and various requests to the ECT/ECU 103. Such control data include “engine rotational speed”, “actual throttle opening degree”, “information relating to engine torque”, “ignition timing”, “information as to whether fuel cut is executing or not”, “rotational speed at which fuel cut is to be stopped”, “estimated time of fuel cut”, “air-conditioning ON/OFF information” or the like. The various requests include “third-gear speed prohibition request”, “fourth-gear speed prohibition request”, “lockup release request” or the like. The data exchange between the ECUs is not limited within the same network. It is therefore necessary for the ECUs belonging to mutually different networks to exchange a great amount of data.